DE2360151B2 - Process for the simultaneous softening and partial dewatering of tubular films as casings for food - Google Patents

Description

Clever casings for edible products such as sausages, for example Viennese sausages, Bolognese sausages and more have been made from regenerated cellulose in a multi-stage process, Made of collagen, amylose, alginate and sometimes polyvinyl alcohol. Generally these are Films made from aqueous solutions of these polymers or polymer derivatives or precursors for these polymers manufactured by extrusion, then formed into a tube, inflated with air and through a Drying device out. The tubular films in the gel state generally contain one considerable amount of water, for example about percent by weight in the case of cellulose films. To the slide so weiterzuverarbeilen. that it takes on the desired properties, the tubular film with Air inflated and passed through a drying device. Drying conditions need to be carefully controlled to prevent the outside of the film from hardening and thereby the passage of Moisture from the inside of the hose to the outside of the film wall when complete Drying is prevented. In order to eliminate the possibility of hardening or breaking of the foils, at moderate temperatures and dried in a stream of air to allow the passage of water vapor through allow the walls. The disadvantage of this drying process is the high cost of the required Device, primarily because of the extensive equipment. Besides, they are

ίο very expensive instruments that are needed to to ensure even drying without hardening of the.-He.

The tubular film made of cellulose, for example is softened before drying by passing it through a glycerine-water solution, which contains 14% glycerin. The residence time in this bath is usually 1 to 2 minutes. At this no significant dewatering of the film is achieved in the usual process stage for softening, because the plasticizer bath is relatively diluted and the dwell time of the film in the bath is too short to to achieve the equilibrium distribution of glycerine and water.

Dilute aqueous glycerol solutions are also used to soften edible collagen casings.

It is also known to soften cellulosic films and to partially dry or dewater by first replacing the film with a glycerine-water mixture, containing 14% glycerine, and the film treated in this way is then passed through an acetone bath. The resulting acetone-water mixture, commonly referred to as the spent phase, is distilled to to recover the acetone. A disadvantage of this procedure is, inter alia, that usually Acetone losses occur, both in the treatment stage and in the recovery of the acetone, and that therefore the manufacturing cost of the film is increased. In addition, in this way of working two process steps are required to effect the desired softening and drainage.

There has now been an improved method of simultaneous softening and partial dewatering of tubular casings for food made from hydrophilic film-forming polymers in the gel state developed.

The invention relates to a process for simultaneous softening and partial dewatering of tubular films made of a hydrophilic polymeric material for casings for food, wherein the tubular film is continuously produced in the gel state and then dried, the characterized in that regenerated cellulose, Cclluloscäther, Cellulose ester, polyvinyl alcohol, polyvinyl ester-polyvinyl alcohol copolymers, alginate polymers, amylose or collagen is used and that the tubular gel sheet is continuously passed through a hygroscopic solution containing 25 to 100 gel

fio weight percentage based on the overall solution polyhydric alcohols with 2 to 12 carbon atoms in the molecule as well as polymeric polyhydric alcohols with 2 to 10 units of polyhydric Alcohols in the structure or on polyamines as

5 pounds of hygroscopic and softening compounds for the gel sheet leads and such a speed maintains that a predetermined amount of water is removed from the foil without affecting the equilibrium

3 4

Distribution of water and plasticizers between hole can have other functions groups,

Gel sheet and solution is achieved. for example an ether group, an epoxy compound

The hvgroscopic solution that the plasticizer dung with the formation of an anhydrous compound, a

for the gel sheet contains, this plasticizer exchanges keto group or an aldehyde group containing the

against the water in the hydrophilic gel sheet. 5 not disadvantageous in the hygroscopic and soft-

With this exchange, water is extracted more quickly, making the polyhydric alcohols

as the plasticizer penetrates the film. They take hold.

Equilibrium distribution of water and soft- Examples of polyhydric alcohols and polymers requires several minutes. The inventiveness polyhydric alcohols include glycerol, polyglycerols proper operation provides that the film _lo Removing having 2 to 10 Giycerineinheiten in the structure and sufficiently long sufficient speed is passed through the hygroscopic solution and fatty acid ester, for example, triglycerol, Dekaglybei, cerin, triglycerol -monostearate, Dekaglycerin-monodamit removes a predetermined amount of water stearate, glycols such as 1,2- and 1,3-propylene glycol, without the hygroscopic agent or the ethylene glycol, polyethylene glycol with 2 to 10 ethylene plasticizers in an undesirably high degree the ₁₅ glycol units in the molecule, sorbitol, mannitol, arabitol foil enters, ie the residence time is shorter than that and dulcitol. Other possible polyhydric alcohols are sugars required to achieve the equilibrium state, preferably the C ₆ and time. Cj, sugars such as glucose, cane sugar, dextrose,

When making tubular casings, treldesirup (a source of glucose), lactose, fructose,

for food, the hydrophilic film-forming 20 becomes levulose. Often a sugar is also used in the mixture

Polymers are first dispersed in water and become one with glycerine or a glycol as hygroscopic

tubular film extruded, which is initially used in the solution.

Gel state and high water content Another class of organic compounds,

owns. It is then in countercurrent (to the solution) which, in the case of gel films, is both hygroscopic and soft.

or act in the same way in conventional columns, pipes, etc., are polyamines, unless they are

by which hygroscopic, plasticizer-containing provisions of the law on foodstuffs conflict,

sung led. Often used as dehydrating agents. Typical representatives for this are alkylenediamines and

and the same agent is used as a plasticizer. their derivatives, for example ethylenediamine, pr

Has the water concentration in the hygroscopic pylenediamine, ethylenediaminetetraacetic acid and their Solution due to absorption of an undesirable extent 30 alkali salts such as sodium ethylenediaminetetraacetate, copper reaches, so the solution is used up and becomes priethylenediamine, diethanolamine, triethanolamine and Recovery of the hygroscopic agent before tetrakishydroxypropylamine. You don't have any notables subtracted from glycerin. The water is lent advantages over polyhydric alcohols, distilled off or removed with the help of an acetone bath, especially not against glycerine when softening fc! nt; then the acetone is removed by means of distillation and dewatering of the film.

recovered. The regenerated hygroscopic for reasons of efficiency and economy solution can be used again, either flexibility and in view of the desired softness immediately in contact with further gel film or making properties that of the desired hydrozur Preparation of fresh hygroscopic solution. philic film made of, for example, cellulose, collagen

One of the hydrophilic polymers in the sense of pre-40 or polyvinyl alcohol is glycerine

lying description, which is used as a means for dewatering and softening

Tubular casings used for food are added. Glycerin can also be used as a minor component in

ν. η and a high proportion of absorbed water, a hygroscopic and plasticizing agent

40 o. , 90% or more, contained in the gel-like film and there with other compounds from the

contain cellulose, collagen, amylose, 45 of the above groups, for example with one

Alginate, hydrolyzed polyvinyl acetate with other polyhydric alcohol such as cane sugar or

moderate hydroxyl content (less than 30% acetate), ζ. Β. Dextrose, be combined.

a polyvinyl acetate-polyvinyl alcohol or polyvinyl The hygroscopic and softening treatment alcohol, Hydroxyalkyl celluloses such as Hydroxymelhyl- lungslösung should be highly concentrated, i. H. 25 to cellulose, hydroxyethyl cellulose, carboxyalkyl cellulose 50 100 percent by weight, based on the total solution, loose such as carboxymethyl cellulose, cellulose acetate, hygroscopic and emollient Cellulose butyrate and cellulose acetate propionate. Off included. Concentrations of 100% can cause inventions the efficiency and economy will be applied accordingly, although this is some-regenerated celluloses Made of viscose, collagen and poly- mal brings me difficulty in steering vinyl alcohol preferred. 55 of the contact period in which a predetermined

The polyvalent and polymeric polyvalent amount of water is removed from the hydrophilic film Alcohols, which are supposed to be both hygroscopic and soft, without the physical intrinsic properties act on the gel sheet, are polyhydroxy shafts of the film by replacing the plasticizing compounds, the hydrogen bonds with the structure are impaired by means of against water. the of the hydrophilic film and an exchange 60 speed of exchange of plasticizer but water from the film against the polyhydroxy against water in a hydrophilic film increases create a bond. In this one point, polyvalent means to be extraordinarily strong if the context that the compounds have two or more plasticizer concentration in the hygroscopic hydroxyl groups, but the solution does not increase, especially above 70 percent by weight necessarily a 65 of the solution on each carbon atom. If, on the other hand, the proportion of hygroscopic hydroxyl group falls must be bound. Of course, the component in the solution may be less than 25 weight but every carbon atom in the molecule is often only a little water out of the molecule carry a hydroxyl group. The polyvalent aiko- hydrophilic film is extracted. Also, Hi?

Treatment is made more difficult as it reaches the equilibrium spaces, depending on the type of hydrc-

conditions are reached too quickly; this means, philic foil, the temperature used, of the in the

that equilibrium is typically found in hygroscopic and hygroscopic and

grooves is achieved. For the sake of an effective emollient and stirring. Example

Overall control of drainage and soaking has been reported by W e 11 i s h, in Journal of

the concentration of hygroscopic Applied Polymer Science, Vol. I, Edition 3, p. 356

and emollient, preferably glycerine, to 360 (1959), Vol. !!, Issue 5, pp. 236 to 240

30 to 90 percent by weight. (1959), and Vol. III, Edition 9, pp. 331 to 337 (1960),

Removing a predetermined larger amount determines that the equilibrium for glycerol-water-water from the hydrophilic film means that these ίο solutions containing about 10% glycerol at 25'C Amount of water is expediently removed, was reached in about 25 seconds. With stronger before the tubular film continues on a concentrated solution, for example at least Final water content dried in a dryer 65% and up to 90 weight percent glycerine (in or is wound up on a supply roll. Generally water), the time was equal to the water content of the hydropilic foils after 15 weight 4 to 8 hours or actually one drying 5 to 30%. The predetermined amount of the day at the higher concentration. In case of Water fluctuates depending on the type of hydrophilic film you want, regardless of the concentration of the glycerine for tubular casings for food and glycerine in the solution, the concentration in the according to the type of envelope sought. Do not make up more than 30% of this water foil. About this value can be 5 to 20 percent by weight in the case of cellulose films, concentrations exceeding 20 value can be added and 10 to 25 percent by weight in the case of collagen foils cause the product to become sticky, especially in the case of be. Cross-linked polyvinyl alcohols and vinyl acetate cellulose.

Vinyl alcohol copolymers in which the proportion The maximum tolerable amounts fluctuate

of functional acetate groups no longer significantly depending on the polymer in the film,

than 15 percent by weight, a water temperature should be 25 The temperature at which the hydrophilic gel sheet

have a content of 5 to 20%. is passed through the hygroscopic solution to

When removing the predetermined amount of water at the same time removing water and making the sheet soft from the hydrophilic film it is important that the amount can be 25 to 75 "C. Higher equilibrium distribution of water and plasticizer temperatures can in some cases be applied between the gel sheet and the solution will not be calibrated to 30. The limit values of the temperature will depend, namely, if equilibrium conditions for the structural strength of the film and of which the concentrated plasticizer is reached or at which the removal of the water is approached, What can be shown by analysis of the film and the replacement of plasticizer is the plasticizer concentration against water in the film, monitored and controlled tration in the film is often too high in the foil, expressed as the feasibility of the process by higher Te Non-volatile fractions of the processed film, in particular somewhat more difficult, because the speed is a special percentage based on the total amount of plasticizer or nygroscopic plasticizer and polymer exchange in the film. In the case of cellulosic agents against water with increasing films, the percentage of plasticizer should increase and often become too high and then, based on the total amount of plasticizer, lead to a film with undesirable properties. Cellulose in the film, not more than 35% by weight, for reasons of efficiency and economy, and preferably at 25 to 30%, it will preferably be at temperatures of 25 to. 40 ⁰ C worked.

Equilibrium or equilibrium conditions are 45 The amount of soft German absorbed by the film in the present case the point at which the maclier can be effectively monitored and in the manner Concentration of plasticizer and hygroscopic can be controlled that one can tell the difference in the The component in the film is roughly the same as the concentration of the softening hygroscopic tration in the solution. It is undesirable for the agent in the gel sheet and mixture to measure and The proportion of plasticizer in the film in equilibrium sees 5 "plotting this value against the line. The recording with the smallest amount of plasticizer, which when these values, i. H. the difference in concentration Put the hygroscopic solution used in the slide and result in the solution against time must, because this makes the physical properties a curve with approximate values for the purpose of the film can be adversely affected; and the film process control so that the plasticizer concen- trates becomes sticky. This is especially true when the film tration after a given contact time Cellulose or collagen can be determined for the hydrophilic film.

and glycerine or a glycol such as ethylene or The foil in the gel state can be replaced by the hygro-propylene glycol as a hygroscopic and plasticizing-scopic treatment solution that contains the plasticizer of the agent is used. If it contains higher concentrations, when inflated or together be carried out on hygroscopic and plasticizing 60 fallen as a flat film. All-means When making the hygroscopic joint, the inflated film can be better handled by hand be applied, for example more than have.

50%, the equilibrium conditions must be The speed with which the gel sheet passes through the

be avoided in any case. In fact, a carefully hygroscopic solution must be drawn, depends self-

care must be taken that the concentration 65 is understandable from the concentration of the hygroscopic

the plasticizer in the film below 50% of the pischen means and the plasticizer in the solution

Concentration is in the solution. away. The period of time within which a given

The equilibrium is achieved in different times - large amount of water from the hydrophilic film

r.

removed is much shorter in the case of a concentrated solution than in the case of a stronger one diluted solution. The pull-through speed should be such that the water content in the finished film is 5 to 30 percent by weight. This water content corresponds to the removal from 25 to 70% of the water originally contained in the film or a total loss of weight from 10 to 50%. For most foils that are used as tubular casings, this period of time 10 to 75 seconds. In some cases, when appropriately suitable hygroscopic Solutions and plasticizers can be used as shown in the examples below the second drying stage, d. H. on inflating the tube or on guiding the inflated one Hose can be dispensed with by a heated dryer. In most cases, however, there will be a second Required drying stage, in which the tubular film is then inflated by a Dryer is run because this is required for conditioning and usually better physical ones Properties of the end product. The following examples serve to provide a more detailed explanation the invention. All percentages relate to weight, unless stated otherwise.

example 1

A number of attempts have been made involving the removal of water from gel cellulose during Explain immersion in a plasticizing hygroscopic solution.

First, a first solution of 300 g of cane sugar, 200 g of glycerine and 300 g of water was prepared by combining the components in a container with mixing. A tubular gel cellulose film, regenerated from viscose and consisting of 70% water and 30% cellulose, was then immersed ^{in this solution for 15 to 20 seconds at a temperature of about 22 ° C.} The visible shrinkage of the film indicated that a substantial amount of water had been removed from the gel cellulose.

A second solution was made that contained 300 g of cane sugar and 200 g of glycerin in 500 g of water contained. A gel cellulose film was immersed in this solution to evaluate removal of water. After immersion for 15 to 20 seconds, the film was pulled out of the solution and passed through Squeeze rollers out. The film was then wiped with a cloth and weighed. The weight loss was 30% and was indicated by slight shrinkage of the film.

Two further experiments were carried out to evaluate the influence of temperature on the removal of water from gel cellulose: a cellulose tube (70% water, 30% cellulose) was added to a solution of 300 g of cane sugar, 200 g of glycerol and 300 g of water 60 ⁰ C immersed; the weight loss was 47%.

If a gel tube of the same type was immersed in a solution of 300 g of cane sugar, 200 g of glycerine and 500 g of water, ^{a weight loss of 33% occurred after immersion for 15 seconds at 24 °} C. and a weight loss of after 15 seconds immersion at 60 ^° C. 40% a.

When the partial dehydration of gel cellulose was carried out continuously, it was as above at the paragraph-wise execution form worked. Gel cellulose (70% water, 30% cellulose), regenerated extracted from viscose and into the usual coagulating, regenerating and washing baths was carried out continuously with a plasticizing or softening hygroscopic bath (300 g cane sugar, 200 g glycerine, 300 g of water) at room temperature and continuously in a conventional dryer dried. The residence time of the gel shell in the softener and drainage bath was 15 to 20 seconds.

The weight loss after exiting the treatment solution was 33%; this corresponded to a reduction of 40% of the load in the dryer. The usual drying devices for tubular gel covers could be shortened by up to 30 m if 40% water was used before passage through the dryer was removed from the casings, for example in the treatment bath. When working continuously, preferably the treatment solution is continuously fed to a distillation plant and there the excess water is distilled off; the regenerated solution then goes back to the treatment stage returned.

B e i s ρ i e 1 2

In a series of experiments, the effect of aqueous glycerol solutions as a treatment bath investigated for the partial dewatering and softening of gel cellulose films. The trials were at four different glycerol concentrations and two different temperatures with one residence time carried out in the treatment bath for 15 seconds. The same results were obtained when working in batches and achieved when working continuously as long as the residence time in the bath was the same. The general The procedure corresponded to that of Example 1.

There were solutions containing 99, 75, 50 and

25% glycerine made in water and used as treatment baths for gelculosic hoses. The temperature of the baths was kept one time at 25 ^° C. and the other time at 60 ^° C. Suitably large sections of gel cellulose casings were added to each bath at the respective temperature as in Example 1. The weight of the gel cellulose casing before and after the treatment was recorded and the glycerol content of the partially dehydrated gel cellulose was determined. The results are summarized in Table 1 below, for each concentration were at ^; Two experiments were carried out at each temperature. The values given for weight loss, glycerol content, cellulose content and percentage glycerol content are the mean values from the two tests at a given temperature.

Example 3

In a series of experiments, tubular gel collagen casings were placed in glycerol-water treatment baths plasticized and partially

Oo waters. The gel collagen sleeves were known in! Manufactured in the manner and passed through the treatment bath after washing, but before drying. Ii The experiments vary in length of dwell time under different conditions Given the same process conditions, the same amount of water is removed from the casing and the same amount of glycerine taken from the shell, regardless of whether the treatment

509520/3 «

occurs intermittently or continuously. When working with desalination, the gel covers were in the bath immersed and then removed. When working continuously, the shells became continuous pulled through the bath and maintained a predetermined residence time in the bath.

Tubular gel collagen sleeves with a diameter of 2 cm and one were used Wall thickness of 0.254 mm; the treatment baths contained 99 and 75% glycerin in water; the dwell times were 20, 35 and 70 seconds. Before and after going through the bathroom, the

10

Collagen casings weighed and the percentage weight loss determined on water. After the treatment, the casings were dried and the giycerin content determined in the collagen shell. The results are summarized in Table 2 below. The results show that both treatment solutions (99 and 75% glycerin in water) are effective the collagen envelopes partially dehydrate if the treatment or residence times are 20 to 70 seconds ίο amount. The concentration of glycerine in the gel shell did not reach an excessively high value during these periods.

Table 1

Glycerin
in the bathroom bath
temperature Weight of Films Weight
loss
Average Glycerine im
dried
Movie Cellulose im
dried
Movie Glycerin
(Cellulose
+ Glycerine) originally after 15 seconds
Immersion (° / o) ( ⁰ C) (8th) (G) (° / o) (S) (B) (° / o)

25th
60

25th
60

25th
60

25th
60

7.00 6.95

7.10 7.15

7.10 7.12

6.93 7.10

6.75 6.75

6.85 6.93

9.20 9.30

9.32

4.22 4.24

3.70 3.80

4.80 4.80

3.70 3.90

4.90 5.10

4.55 4.50

7.90 7.95

7.42

0.3225 1.1180 22.4 0.7058 1.7432 28.8 0.4817 1.7381 21.7 0.7431 1.8018 29.2 0.4159 1.7290 19.4 0.6638 1.7415 27.6 0.8612 2.3425 26.8 0.7525 2.405 23.8

Table 2 Glycerin Shell weight after this Weight Stay Badtem Glycerine im Collagen im Glycerin in the bathroom Immersion loss line temperature drying film drying film (Glycerin originally (G) + Collagen) 18.6 ( ⁰ O) (B) 15.0 ( ⁰ O) (s) ( ⁰ C) (8th) (G) (Vo) 99 22.7 14.9 18.1 35 25th 0.4831 1.6081 23.0 1 99 21.7 15.3 28.1 70 25th 0.7469 1.5726 30.8 2 99 19.4 11.2 23.2 35 25th 0.3989 1.3855 22.3 3 75 18.15 13.2 15.7 35 25th 1.3444 1.3306 50.2 4th 75 13.3 9.8 15.7 35 25th 0.9289 0.9683 50.0 5 75 21.15 13.4 37.6 35 60 0.4481 1.5996 22.0 6th 99 19.5 12.0 49.7 35 70 0.4108 1.4420 22.0 7th 99 27.5 15.1 51.3 35 70 0.5462 2.0376 21.1 8th 99 21.6 13.0 44.4 20th 70 0.6208 1.6683 27.1 9 99 28.5 13.1 50.0 20th 70 0.7609 2.2229 23.9 10 99 28.4 54.2 20th 90 1.6711 2.2594 42.8 11 99 28.5 54.1 20th 90 1.7085 2.3013 45.1 12th

879

Example 4

Contains 10 g of polyvinyl alcohol film in a gel state prepared by hydrolysis of polyvinyl acetate 80 percent by weight water. The 10 g sample shrank when immersed in an aqueous solution of cane sugar and glycerin containing 30% glycerin and 20% cane sugar, and lost weight. The gel film lost 40% water (weight) with a treatment time of 35 seconds. The softening treatment and partial dewatering could be done batchwise or continuously.

Example 5

A gel cellulose film made of viscose was ( Immersed in an aqueous solution containing 50% ethylenediamine for 30 seconds at room temperature and shrank with this treatment. The treatment could be carried out intermittently or continuously as described in Example 1. The weight loss of the treated film showed that a substantial Licher portion of water had been removed from the film. During this dwell time seh diffused little ethylenediamine in the film, and the equilibrium conditions were not achieved.

879

Claims (4)

Patent claims: 1. A process for the simultaneous soft maceration and partial dewatering of tubular films made of a hydrophilic material; polymeric material for casings for foodstuffs, the tubular film being produced continuously in the gel state and then dried, characterized in that regenerated cellulose, cellulose ether, cellulose ester, polyvinyl alcohol, polyvinyl ester-polyvinyl alcohol copolymers, alginate polymers, amylose or collagen is used as the hydrophilic polymeric film material and that the tubular gel film is continuously passed through a hygroscopic solution containing 25 to 100 percent by weight, based on the total solution, of polyhydric alcohols with 2 to 12 carbon atoms in the molecule and polymeric polyhydric alcohols with 2 to 10 units of polyhydric alcohols in the structure or of polyamines as leads to hygroscopic and plasticizing compounds for the gel film and maintains such a speed that a predetermined amount of water is removed from the film without the equilibrium distribution of water and plasticizer between the gel film and the solution is achieved. 2. The method according to claim 1, characterized in that one maintains a residence time in the mixture of polyhydric alcohol and water which corresponds to _{a reduction in the water content of the film of 5 to 30 "o.} 3. The method according to claim 1 or 2, characterized in that the polyhydric alcohol Glycerin, ethylene glycol, propylene glycol and cane sugar as well as their mixtures are used. 4. The method according to any one of claims 1 to 3, characterized in that the hygroscopic Solution regenerates when its water content is more than 75% and the regenerated solution used for a further treatment of film material.